Hydrothermal　stability　of　the　Cu(A,　N,　Cl　or　S)/SAPO.34　samples　derived　from　different　Cu　precursors　(A:　Cuacetate;　N:　Cu-nitrate;　Cl:　Cu-chloride;　and　S:　Cu-sulfate)　was　investigated.　The　physical　and　chemical　properties　of　the　samples　were　investigated　by　various　analytical　techniques,　and　their　catalytic　activities　for　NO　conversion　and　NH3　oxidation　were　evaluated.　The　results　of　NH3-SCR　activity　show　that　the　Cu(A)/SAPO-34　sample　was　better　than　that　of　the　Cu(N,　Cl　or　S)/SAPO-34　sample,　which　was　due　to　the　existence　of　a　less　amount　of　CuO　species　and　a　more　amount　of　the　isolated　Cu2+　species.　Moreover,　catalytic　activities　of　all　aged　catalysts　decreased　in　the　whole　temperature　range,　which　was　attributed　to　the　drop　in　the　amount　of　isolated　Cu2+　species　in　the　hydrothermally　treated　Cu/SAPO-34　samples.　After　hydrothermal　aging　treatment,　part　of　the　isolated　Cu2+　was　transformed　to　CuO,　leading　to　structural　instability　and　deactivation　of　the　catalysts.